U.S. patent application number 15/965493 was filed with the patent office on 2019-01-03 for independent propeller/main rotor speed control for x2 technology.
The applicant listed for this patent is Sikorsky Aircraft Corporation. Invention is credited to Derek H. Geiger, Jonathan Aaron Litwin, Michael Peter Strauss, Ole Wulff.
Application Number | 20190002095 15/965493 |
Document ID | / |
Family ID | 62089605 |
Filed Date | 2019-01-03 |
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United States Patent
Application |
20190002095 |
Kind Code |
A1 |
Geiger; Derek H. ; et
al. |
January 3, 2019 |
INDEPENDENT PROPELLER/MAIN ROTOR SPEED CONTROL FOR X2
TECHNOLOGY
Abstract
A rotary-wing aircraft and system for controlling a flight of
the rotary-wing aircraft. The aircraft includes a main rotor, a
propeller and a variable speed transmission for transferring power
from the main rotor to the propeller. A propeller command module
controls operation of the variable speed transmission. The
propeller command module varies a transfer of power from the main
rotor to the propeller.
Inventors: |
Geiger; Derek H.; (Wilton,
CT) ; Wulff; Ole; (Ansonia, CT) ; Litwin;
Jonathan Aaron; (West Haven, CT) ; Strauss; Michael
Peter; (New Haven, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sikorsky Aircraft Corporation |
Stratford |
CT |
US |
|
|
Family ID: |
62089605 |
Appl. No.: |
15/965493 |
Filed: |
April 27, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62526029 |
Jun 28, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64C 27/82 20130101;
B64C 27/12 20130101; B64C 2027/8281 20130101; B64D 35/00 20130101;
B64C 2027/8236 20130101; B64C 27/10 20130101; B64C 2027/8272
20130101 |
International
Class: |
B64C 27/12 20060101
B64C027/12; B64C 27/10 20060101 B64C027/10; B64C 27/82 20060101
B64C027/82 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] There are Government rights associated with this matter,
contract #W911W6-14-2-0005.
Claims
1. A rotary-wing aircraft, comprising: a main rotor; a propeller; a
variable speed transmission for transferring power from the main
rotor to the propeller; and a propeller command module that
controls operation of the variable speed transmission.
2. The rotary-wing aircraft of claim 1, wherein the propeller
command module provides a command to the variable speed
transmission to control the operation of the variable speed
transmission.
3. The rotary-wing aircraft of claim 1, further comprising a main
rotor gearbox associated with the main rotor and a propeller
gearbox associated with the propeller, wherein the propeller
command module provides a propeller gearbox command to the
propeller gearbox to vary a speed ratio between the main rotor
gearbox and the propeller gearbox.
4. The rotary-wing aircraft of claim 3, wherein varying the speed
ratio further comprises varying a gear ratio between the main rotor
gearbox and the propeller gearbox.
5. The rotary-wing aircraft of claim 4, wherein the propeller
command module further generates a propeller gearbox command to
control the gear ratio between the main rotor gearbox and propeller
gearbox.
6. The rotary-wing aircraft of claim 1, wherein the propeller
command module further generates a propeller blade pitch
command.
7. The rotary-wing aircraft of claim 3, wherein the propeller
command module receives a main rotor turbine speed reference value
and generates the propeller gearbox command based, at least in
part, on the main rotor turbine speed reference value.
8. The rotary-wing aircraft of claim 1, wherein the propeller
command module provides at least one of a propeller rotor speed and
a propeller torque to an engine command module.
9. A system for controlling a flight of a rotary-wing aircraft,
comprising: a variable speed transmission for transferring power
from a main rotor of the aircraft to a propeller of the aircraft;
and a propeller command module that controls operation of the
variable speed transmission to vary a transfer of power from the
main rotor to the propeller.
10. The system of claim 10, wherein the propeller command module
provides a command to the variable speed transmission to control
the operation of the variable speed transmission.
11. The system of claim 9, wherein the aircraft further includes a
main rotor gearbox associated with the main rotor and a propeller
gearbox associated with the propeller, wherein the propeller
command module provides a propeller gearbox command to the
propeller gearbox to vary a speed ratio between the main rotor
gearbox and the propeller gearbox.
12. The system of claim 11, wherein the speed ratio further
comprises a gear ratio between the main rotor gearbox and the
propeller gearbox.
13. The system of claim 12, wherein the propeller command module
generates a propeller gearbox command to control the gear ratio
between the main rotor and propeller.
14. The system of claim 9, wherein the propeller command module
further generates a propeller blade pitch command.
15. The system of claim 11, wherein the propeller command module
generates the propeller gearbox command based, at least in part, on
a reference turbine speed of the main rotor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
patent application Ser. No. 62/526,029 filed Jun. 28, 2017, the
entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0003] The present invention is directed to power transmission
between a main rotor of a rotary-wing aircraft and a propeller of
the rotary-wing aircraft and, in particular, to a system for
providing a variable transmission to control a ratio of rotor
speeds between the main rotor and the propeller.
[0004] Rotary-wing aircraft include engines that provide torque to
rotate a main rotor and thereby provide lift to the aircraft. A set
of propeller blades can be placed at the rear of the aircraft in
order to provide forward thrust to the aircraft. The propeller and
the main rotor are coupled through a constant speed gearbox. Due to
their coupling via the constant speed gearbox, a reduction in a
main rotor speed at a high speed forward flight causes a
simultaneous reduction a propeller speed, causing a loss of forward
thrust, which may or may not be desirable. Furthermore, the
efficiency of both the main rotor and the propeller can be
optimized by operating each system at independent rotational
speeds. Thus, there is a need to be able to vary speeds of the main
rotor and the propeller independently.
SUMMARY OF THE INVENTION
[0005] According to one embodiment of the present invention, a
rotary-wing aircraft, including: a main rotor; a propeller; a
variable speed transmission for transferring power from the main
rotor to the propeller; and a propeller command module that
controls operation of the variable speed transmission.
[0006] According to another embodiment of the present invention, a
system for controlling a flight of a rotary-wing aircraft,
including: a variable speed transmission for transferring power
from a main rotor of the aircraft to a propeller of the aircraft;
and a propeller command module that controls operation of the
variable speed transmission to vary a transfer of power from the
main rotor to the propeller.
[0007] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0009] FIG. 1 depicts an exemplary embodiment of a coaxial rotary
wing, vertical takeoff and land (VTOL) aircraft;
[0010] FIG. 2 shows a schematic diagram of a flight system for
providing a variable speed transmission to a rotary-wing aircraft
such as the exemplary aircraft of FIG. 1.
DETAILED DESCRIPTION
[0011] Referring now to the Figures, where the invention will be
described with reference to specific embodiments, without limiting
same, FIG. 1 depicts an exemplary embodiment of a coaxial rotary
wing, vertical takeoff and land (VTOL) aircraft 10. The aircraft 10
includes an airframe 12 with an extending tail 14. A dual, counter
rotating, coaxial main rotor assembly 18 is located at the airframe
12 and rotates about a main rotor axis, A. In an exemplary
embodiment, the airframe 12 includes a cockpit 15 having two seats
for flight crew (e.g., pilot and co-pilot) and six seats for
passengers (not shown). Main rotor assembly 18 is driven by a power
source, for example, one or more engines 24 via a main rotor
gearbox 26. Main rotor assembly 18 includes an upper rotor assembly
28 driven in a first direction (e.g., counter-clockwise) about the
main rotor axis, A, and a lower rotor assembly 32 driven in a
second direction (e.g., clockwise) about the main rotor axis, A,
opposite to the first direction (i.e., counter rotating rotors).
Upper rotor assembly 28 includes a first plurality of rotor blades
38 supported by a first rotor hub 39. Lower rotor assembly 32
includes a second plurality of rotor blades 34 supported by a
second rotor hub 36. The first plurality of rotor blades 38 rotate
through a first rotor disk and the second plurality of rotor blades
34 rotate through a second rotor disk. In some embodiments, the
aircraft 10 further includes a translational thrust system 40
having a propeller 42 located at the extending tail 14 to provide
translational thrust (forward or rearward) for aircraft 10.
[0012] Translational thrust system 40 may be mounted to the rear of
the airframe 12 to provide thrust for high-speed flight. While
shown in the context of a pusher-prop configuration, it is
understood that the propeller 42 could also be a more conventional
puller prop or could be variably facing so as to provide yaw
control in addition to, or instead of, translational thrust. It
should be understood that any such system or other translational
thrust systems may alternatively or additionally be utilized.
Alternative translational thrust systems may include different
propulsion forms, such as a jet engine.
[0013] In accordance with an aspect of an exemplary embodiment,
propeller blades 43 of translational thrust system 40 may include a
variable pitch. More specifically, the pitch of propeller blades 43
may be altered to change the direction of thrust (e.g., forward or
rearward). In accordance with another aspect of an exemplary
embodiment, extended tail 14 includes a tail section 50 including
starboard and port horizontal stabilizers 51 and 52. Tail section
50 also includes a vertical stabilizer 53 that extends downward
from extending tail 14. Starboard horizontal stabilizer 51 includes
a starboard active elevator 54 and a starboard active rudder 56.
Similarly, port horizontal stabilizer 52 includes a port active
elevator 58 and a port active rudder 60. Elevators 54 and 58 and
rudders 56 and 60 act as controllable flight surfaces, e.g.,
surfaces that alter a flight path/characteristics of aircraft
10.
[0014] Propeller 42, or translational thrust system 40, is
connected to, and driven by, the one or more engines 24 via a
propeller gearbox 46. The propeller gearbox 46 is driven by the
main rotor gearbox 26. The propeller gearbox 46 is capable of
changing a gear ratio between the main rotor gearbox 26 and the
propeller gearbox 46 so that the relative speeds between the main
rotor gearbox 26 and the propeller gearbox 46 can be varied on
command. The variable gear ratio of the propeller gearbox 46
controls how much speed and power are transmitted from the main
rotor gearbox 26 to the propeller gearbox 46.
[0015] Aircraft 10 includes a flight control system 70 for
controlling flight of the aircraft 10. In particular, the flight
control system 70 includes a processor (not shown) that executes a
flight control system that controls a gear ratio at the propeller
gearbox 46 of the aircraft 10 in order to vary a speed ratio
between the main rotor gearbox 26 and the propeller gearbox 46. A
detailed discussion of the flight control system 70 is provided
below with respect to FIG. 2.
[0016] FIG. 2 shows a schematic diagram of a flight control system
200 for providing a variable speed transmission to a rotary-wing
aircraft such as the exemplary aircraft 10 of FIG. 1. The flight
control system 200 includes a flight control laws module 202, an
engine command module 204, a propeller command module 206 and a
full authority digital engine control (FADEC) 208, which can be
operated on one or more processors of the flight control system
200. The hardware of aircraft 10 is represented in FIG. 2 by engine
1 (210), engine 2 (212) main rotor gearbox 214, main rotor 216,
propeller gearbox 218 and propeller 220. The flight control laws
module 202 receives pilot input from the pilot through various
pilot interfaces, such as a cyclic, collective, pedals or any other
suitable interface. The flight control laws module 202 receives the
pilot input and determines various flight control commands to be
applied at the aircraft 10 in order to implement the pilot input.
For example, the flight control laws module 202 can determine
flight commands for the main rotor 216 of the aircraft 10, such
main rotor flight commands including pitch, roll and yaw of the
main rotor 216 as well as collective commands, for example.
Additionally, the flight control laws module 202 determines flight
commands for the propeller 220, such as propeller thrust commands.
The flight control laws module 202 provides the main rotor flight
commands to the engine command module 204 and the propeller flight
commands to the propeller command module 206.
[0017] The engine command module 204 receives the main rotor flight
commands from the flight control laws module 202 and determines
suitable torque (Q cmd) and rotor speed (Np cmd) commands for
implementing the main rotor flight commands at the aircraft 10. The
determined torque and rotor speed commands are provided to the
FADEC 208, which implements the torque and rotor speed commands at
at least one of engine 1 (210) and engine 2 (212). At least one of
the engines (e.g., engine 1 (210)) may provide feedback to the
FADEC 208 in order to enable the FADEC 208 regulate operation of
the engines. One or more of engine 1 (210) and engine 2 (212)
provides a selected turbine speed (Np) to the main rotor gearbox
214. The main rotor gearbox 214, powered at the selected turbine
speed (Np), rotates the main rotor 216 of the aircraft 10 at a
selected rotor speed (Nr). The main rotor 216 further provides an
input speed to the propeller gearbox 216. It is to be noted that
the engine power turbine speed (Np at engines 1 and 2), the main
rotor speed (Nr) and the gearbox input speed from the main rotor
216 are all coupled or have a mathematical relation to each
other.
[0018] In addition to rotating the rotor blades, the main rotor
gearbox 214 is coupled to the propeller gearbox 218 and thereby
provides power to the propeller gearbox 218. The activation of the
propeller gearbox 218 provides a selected propeller speed (Nr Prop)
to the propeller 220. The speed of the propeller gearbox 216 and
therefore of the propeller blades 220 is controlled in part by the
speed provided from the main rotor gearbox 214 and in part by a
propeller gearbox command received from the propeller command
module 206.
[0019] The propeller command module 206 controls operation of the
propeller gearbox 218, specifically controlling the speed of the
propeller gearbox 218 relative to the speed main rotor gearbox 214.
In one embodiment, the propeller gearbox 218 changes a gear ratio
as indicated by a propeller gearbox command provided by the
propeller command module 206. The propeller command module 206 also
controls a pitch of the blades of propeller 220. The propeller
command module 206 receives a propeller thrust command from the
flight control laws module 202 and provides a propeller gearbox
command to the propeller gearbox 218 and a propeller blade pitch
command to the propeller 220. The propeller gearbox command and the
propeller blade pitch command are determined at least in part based
on the propeller thrust command. The propeller gearbox command
controls a gear ratio of the propeller gearbox 218 and therefore
controls a speed of the propeller gearbox 218 relative to the speed
of the main rotor gearbox 214. Therefore, the speed of the
propeller gearbox 218 relative to the speed of the main rotor
gearbox 214 can be varied as desired. The propeller gearbox 218 can
change a gear ratio in response to the propeller gearbox command in
order to obtain an optimal or selected propeller speed (Nr prop) at
the propeller gearbox 218. The propeller blade pitch command
controls a pitch of a blade of the propeller 220.
[0020] The engine command module 204 and the propeller command
module 206 communicate information to each other. The communication
information can be used by the engine command module 204 and the
propeller command module 206 to determine their respective output.
For example, the engine command module 204 provides a main rotor
turbine speed reference value to the propeller command module 206
and the propeller command module 206 can determine a suitable
propeller gearbox command as well as the propeller blade pitch
command based, at least in part, on the main rotor turbine speed
reference value. In addition, the propeller command module 206 can
provide a propeller rotor speed and propeller torque to the engine
command module 204. The engine command module 204 can determine the
main rotor torque and main rotor turbine speed based, in part, on
the propeller rotor speed and propeller torque provide from the
propeller command module 206.
[0021] In various aspects, the propeller gearbox 218 includes the
elements of a variable speed transmission therein for controlling
gear ratios, gear speeds, etc., in response to a propeller gearbox
command. In alternate embodiments, the variable speed transmission
can be a separate component of the aircraft that is mechanically
connected to the main rotor gearbox 214 as well as to the propeller
gearbox 218 and receives the propeller gearbox command from the
propeller command module 206 in order to vary power transfer, speed
transfer, gear ratios, etc.
[0022] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description.
* * * * *